Effectiveness of vaccination and/or antibiotics to control Coxiella burnetii infection in dairy herds

Transcription

1 Effectiveness of vaccination and/or antibiotics to control Coxiella burnetii infection in dairy herds Raphaël Guatteo, Taurel A-F, Joly A., Beaudeau F. UMR Oniris-INRA 1300 BioEpAR

2 State of Knowledge about control measures Non medical actions Not specific Hygiene of Calving pen, Detection-Destruction placenta

3 State of Knowledge about control measures Non medical actions Not specific Hygiene of Calving pen, Detection-Destruction placenta Medical actions Antibiotics Effectiveness?

4 Antibiotics? Antibiotics (tetracyclins) Limit abortions, Don t stop shedding Old studies: less sensitive methods for detection of Cb Therapeutic scheme? : Not Evidence based Need for rational use Woernle et al., 1985 Behymer et al., 1977 Population 2 cows, no control 33 cows, 20 control Regimen IM, 21 days before calving Per os, 61 & 31 days before calving Detection method Stamp machiavello Micro-agglutination Real effectiveness of Antibiotics At which regimen?

5 State of Knowledge about control measures Non medical actions Not specific Hygiene of Calving pen, Detection-Destruction placenta Medical actions Antibiotics Effectiveness? Medical actions Vaccination Effectiveness +++ on heifers to prevent shedding Cows? Beyond shedding?

6 Aim of the study To assess the effectiveness of different medical strategies combining vaccination and/or antibiotics To prevent and/or reduce Coxiella burnetii shedding To prevent or reduce Clinical signs related to Q fever To improve reproduction performances

7 Material and Methods 120 Dairy Herds (repeated abortions related to Q fever) Vaccination Common treatment for all herds VACCINATION of Nulliparous (Guatteo et al., 2008) Antibiotics Vaccination Antibiotics None R A N D O M Phase 1 Vaccine (Coxevac, CEVA Santé Animale), Long acting Oxytetracycline (20mg/kg, TENALINE LA, CEVA Santé Animale) In herds with «Antibiotics» : cows assigned at random:? 1 or 2 administrations at drying off? 1 administration at calving? 1 or 2 administrations at drying off and calving

8 Material and Methods Comparison of abortions and retained placenta occurrence (-6 : +12 m) between groups Description of return to service rate between groups Animal Vaginal Swabs (22 herds) At calving Herd BTM or Primiparous mix Monthly or quarterly Environment Bedding material Effectiveness to reduce/ prevent Cb shedding at individual level Indicator of Cb circulation at herd level Environmental Cb Load Effectiveness of bedding removal

9 Prevention of Shedding at calving time Vaccination : no preventive effect in cows Vaccination in heifers (some heifers not vaccinated) : OR: 0.17, [ ] Variable N % shedder cows Total Risk of shedding OR P-value Antibiotics at drying off 0.01 None Once Twice Once at drying off : prevention of shedding occurrence No added value of a second administration High variability between herds [Prev shedders: 2 38%] Need for targeting at risk herds (seasonal calving, shedding +++)

10 Reduction of Cb load at calving time Antibiotics: no effect Variable N Cb load > vs. ]0-100] b/ml OR P Vaccination 0.03 None 76 1 After service Before service Initial serological status 0.01 Positive 97 1 Negative Age at calving ns Vaccination (cows and heifers) : Reduction of Cb load shed when shedding occurred Reduction of the transmission rate

11 Reduction of shedding at herd level 74 herds, 354 BTM samples, 5254 dairy cows Antibiotics: no effect (not expected) Favourable pattern in BTM (reduction of Cb load over time) Vaccination covering rate 0-20% Vaccination covering rate 20-80% Vaccination covering rate >80% 0,29 0,17 1 Whole herd vaccination (>80%) : Strong and fast reductio nof Cb shedding at herd level Perspectives : duration of vaccination, DIVA tests

12 Reduction of shedding at herd level Cb load in mix of primiparous milk Confirmation of interest of nulliparous vaccination 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% D0 D90 D180 D270 D360 D450 D540 Negative «Low Cb load» «Moderate Cb load» «High Cb load» «High +++ Cb load»

13 Bedding material (renewal) 100% Reduction of Cb load in environment Interest of vaccination to reduce Cb load Interest of bedding renewal to decrease infectious pressure Exploratory method, confirmation in different contexts 80% 60% 40% 20% 0% D0 D90 D180 D270 D360 D450 D540 Negative «Low Cb load» «Moderate Cb load» «High Cb load» «High ++ Cb load»

14 Effectiveness to prevent clinical signs Clinical signs Abortions Résultats Vaccination: OR : 0,694 [ ] (P=0.09) Seropositivity (p<0.05) : OR : 2,547 [ ] Séropositivity (p<0.05) : OR: [ ] Retained placenta ATB once at drying off : lower risk (p<0.05) Confirmation of implication of Coxiella in reproductive disorders Trend to reduce abortions in cows Co-infections? / Scarce events

15 Effectiveness to improve fertility Return to service (18-26 d) Return to service (27-90 d) Vaccination in nulliparous Vaccination in Cows ATB at calving ns ns ns OR : 0,538 [ ] (p<0.05 ns OR: [ ] (P<0.05) Confirmation of interest of vaccination in nulliparous Limited effect of antibiotics

16 To summarize Ambitious Design (N herds, N cows, sensitive methods) Confirmation of the interest +++ of vaccination in nulliparous Arguments for vaccinating cows : shedding, clinical signs, fertility Basis for rationale use of Antibiotics (specific cows, once only) Perspectives Duration of vaccination, Cost-benefit approach Vaccination Antibiotics once at drying off Antibiotics at calving Abortions Occurrence? Not expected Retained placenta? Occurrence? Impaired fertility Return to service No effect Return to service in seropostive Cb shedding Reduction of shedding Prevention of shedding?

17 In practice.,. Abortions du to Coxiella burnetii (Positive PCR on aborted foetus, placenta or vaginal mucus) Non Medical Control Measures Medical Control Measures - Restriction of Introduction - Disinfection of calving box after each calving - Separate box calving - Destruction of placentas - Avoid spreading manure when wind blows Oxytetra at drying off once Case of seasonal calving +++ High prevalence of shedders Vaccination Heifers at least Cows : reduction of abortion and faster reduction of Cb shedding Achievment of strong and fast reduction of Cb shedding

18 Acknowledgements All the cows, farmers and vets included in the study... In memory of Christophe Manteca

19 Descriptive results : abortions Abor%on rate % Within herd abortion rate (median) according to treatment group before inclusion aaer inclusion 3,8 5 3,3 4,5 2,3 2,4 2,1 2,2 Vaccin Vacc + ATBQ ATBQ Control